A cross-layer optimized storage system for workflow applications

This paper proposes using file system custom metadata as a bidirectional communication channel between applications and the storage middleware. This channel can be used to pass hints that enable cross-layer optimizations, an option hindered today by the ossified file-system interface. We study this approach in the context of storage system support for large-scale workflow execution systems: Our workflow-optimized storage system (WOSS), exploits application hints to provide per-file optimized operations, and exposes data location to enable location-aware scheduling. We argue that an incremental adoption path for adopting cross-layer optimizations in storage exists, present the system architecture for a workflow-optimized storage system and its integration with a workflow runtime engine, and evaluate this approach using synthetic and real applications over multiple success metrics (application runtime, generated network stress, and energy). Our performance evaluation demonstrates that this design brings sizeable performance gains. On a large scale cluster (100 nodes), compared to two production class distributed storage systems (Ceph and GlusterFS), WOSS achieves up to 6× better performance for the synthetic benchmarks and 20-40% better application-level performance gain for real applications.